Maskarinec Gertraud, Jacobs Simone, Park Song-Yi, Haiman Christopher A, Setiawan Veronica W, Wilkens Lynne R, Le Marchand Loïc
Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii.
Department of Preventive Medicine, Keck School of Medicine, and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California.
Cancer Epidemiol Biomarkers Prev. 2017 Jun;26(6):854-861. doi: 10.1158/1055-9965.EPI-16-0789. Epub 2017 Jan 13.
Obesity has been more consistently associated with breast cancer than type II diabetes. This analysis examined the combination of the two factors in the Multiethnic Cohort (MEC). Women ages 45-75 years entered the MEC in 1993-1996 by completing a questionnaire. Type II diabetes status was self-reported at baseline, two follow-up questionnaires, and confirmed by administrative data. Cancers were identified from tumor registries and deaths through vital records until 2010. Cox regression was applied to estimate HRs and 95% confidence intervals (CI) for BMI and type II diabetes status alone and in combination. Among 103,721 (25,146 white, 20,255 African American, 7,681 Native Hawaiian, 28,012 Japanese American, 22,627 Latina) women with 14,558 type II diabetes cases, 6,692 women developed breast cancer during 14.8 ± 4.1 years of follow-up. Type II diabetes was significantly associated with breast cancer risk (HR, 1.15; 95% CI, 1.07-1.23), but including body mass index (BMI) lowered the HR to 1.08 (95% CI, 1.00-1.16). Ethnic-specific BMI-adjusted models showed elevated risks for type II diabetes in Latinas only (HR, 1.30; 95% CI, 1.11-1.52). In contrast, obesity predicted statistically significant 21%-46% higher risks, after type II diabetes adjustment, in all ethnic groups except Latinas (HR, 1.17; 95% CI, 0.99-1.38). As reported previously, inclusion of BMI weakened the association of type II diabetes with breast cancer. Type II diabetes status, but not BMI, was primarily associated with higher breast cancer risk in Latinas. The role of obesity and type II diabetes in breast cancer etiology may differ by ethnicity suggesting metabolic differences related to obesity. .
与II型糖尿病相比，肥胖与乳腺癌的关联更为一致。本分析在多族裔队列（MEC）中研究了这两个因素的组合情况。1993年至1996年期间，45至75岁的女性通过填写问卷进入MEC。II型糖尿病状态在基线、两份随访问卷中由自我报告，并经行政数据确认。通过肿瘤登记处和生命记录确定癌症情况，直至2010年。应用Cox回归单独和联合估计BMI和II型糖尿病状态的风险比（HR）及95%置信区间（CI）。在103,721名（25,146名白人、20,255名非裔美国人、7,681名夏威夷原住民、28,012名日裔美国人、22,627名拉丁裔）女性中，有14,558例II型糖尿病病例，在14.8±4.1年的随访期间，6,692名女性患乳腺癌。II型糖尿病与乳腺癌风险显著相关（HR，1.15；95%CI，1.07 - 1.23），但纳入体重指数（BMI）后，HR降至1.08（95%CI，1.00 - 1.16）。特定族裔的BMI调整模型显示，仅拉丁裔女性的II型糖尿病风险升高（HR，1.30；95%CI，1.11 - 1.52）。相比之下，在除拉丁裔外的所有族裔中，调整II型糖尿病后，肥胖预测的风险在统计学上显著高出21% - 46%（HR，1.17；95%CI，0.99 - 1.38）。如先前报道，纳入BMI会削弱II型糖尿病与乳腺癌的关联。在拉丁裔女性中，主要是II型糖尿病状态而非BMI与较高的乳腺癌风险相关。肥胖和II型糖尿病在乳腺癌病因中的作用可能因种族而异，这表明与肥胖相关的代谢差异。
